Zn dendrite suppression and solid electrolyte interface control using N-allylthiourea as an electrolyte additive for aqueous Zn-ion batteries

Abstract

Despite being promising candidates for Li-ion batteries, the development of aqueous Zn-ion batteries is still impeded by inherent unresolved problems such as dendrite growth and side reactions on the anode side. In this study, a stabilized Zn-electrolyte interface is established using N-allylthiourea (ATU) as an additive in mildly acidic electrolytes because of its strong affinity towards Zn2+ ions and the Zn metal. Through this favorable electrostatic adsorption, side reactions owing to water molecules are inhibited, and uniform Zn deposition is achieved, leading to highly reversible stripping/plating performance. Consequently, a stable cycling performance of up to 500 h at a current density of 1 mA cm-2 and an areal capacity of 1 mAh cm-2 is demonstrated for Zn symmetric cells. Furthermore, a Zn|VO2 full cell validates the possible practical use of ATU where it delivers a promising cycling performance of up to 300 cycles at a current rate of 1C (200 mA g-1). This study contributes insights into the role of additives in optimizing battery performance and creates opportunities for further exploration of similar compounds in pursuit of sustainable energy storage systems.